Question

a circular well of radius 4.2 metre is dug 7 metre deep. if removing 1m cube of soil cost rupees 80 find the expenditure on digging the well​

Answer 1

Step-by-step explanation:

Given, Diameter =4 m

Radius =2 m h=21 m

V=πr

2

h=π(2)(2)(21)=84π

Volume of soil dug from well = volume of earth used to form embankment

⇒84π=π(5

2

−2

2

)h

h=

25−4

84

=

21

84

=4m

Answer 2

Given, Diameter =4 m

Radius =2 m h=21 m

V=πr

2

h=π(2)(2)(21)=84π

Volume of soil dug from well = volume of earth used to form embankment

⇒84π=π(5

2

−2

2

)h

h=

25−4

84

=

21

84

=4m